1. Field of the Invention
This invention relates generally to a microphone able to capture audio in spite of ambient noise and oncoming wind.
2. Description of Related Art
Since its invention, the microphone has been used in a multitude of varying applications. Seen in consumer products such as telephones, hearing aids, and computers, as well as industry specific applications such as audio engineering, movie production, and broadcasting, the microphone has become an integral part of modern technology. The microphone is used in devices which record, amplify, and transmit sound over long distances. For all of its uses, however, the microphone has always contained one specific flaw: the capture of unwanted sound.
The basic microphone works as a catch-all, capturing all sound waves around it whether the user intends to capture them or not. This has forced many microphone users to seek out perfectly quiet areas before use, to attempt to remove unwanted sound using complex computer software, or to simply accept an imperfect capture of the sound they targeted. In some uses this may not be a problem or may actually be intended, but in many other applications a perfect capture of the desired audio is critical. Further, in some settings, the ambient noise may be so great as to entirely drown out the sound to be captured.
The noise-cancelling microphone attempts to remove ambient noise from a captured signal and, for the most part, does a satisfactory job. Noise-cancelling microphones are sensitive to sound one two opposite sides. One “capture side” is oriented toward the source of the desired sound, and another “cancelling side” is oriented away from the source of desired sound. Both sides still capture all ambient noise, but the cancelling side does not pick up the sound from the desired source. The noise-cancelling microphone then uses the signal from the cancelling side to cancel out part of the signal from the capture side, ideally leaving only the sound captured from the desired sound source and nothing more.
One arrangement of a noise-cancelling microphone is a bidirectional or “Figure-8” microphone. This type of microphone includes a front and a back side, but includes only one voice coil. Thus, as described above, the front of the voice coil serves as the capture side, while the back of voice coil serves as the cancelling side.
While the noise-cancelling microphone performs well when cancelling out ambient noise picked up by both sides, it ignores the effect of sound and other vibrations directed toward and picked up by the cancelling side only. Any sound picked up by the cancelling side but not the capture side will introduce new noise into the final signal during the noise-cancelling process, thus defeating the purpose of the noise-cancelling microphone in the first place. Such sounds could result from a person speaking directly in front of the cancelling side or wind directed toward the cancelling side. Wind-induced noise is especially troublesome in areas such as motorsports, where noise-cancelling microphones are often used.
In many motorsports, drivers use headsets employing noise-cancelling microphones to communicate with their crew chief or other team members throughout the race while cancelling out the sound of the vehicle's engine. Such communication is critical to the driver's safety and performance, as it enables the driver to know much more about the state of the racetrack than can be immediately observed and to plan strategies with team members to avoid accidents and pass opponents. Not all motorized vehicles confer the benefit of a full windshield, however, exposing the driver to a constant, high-power headwind. As explained above, such a headwind would be directed toward the cancelling side of the noise-cancelling microphone, resulting in the addition of wind noise to the final, post-cancellation signal. Foam windshields have been developed to attempt to alleviate this problem, but prove to be imperfect solutions, particularly when the force of the wind is strong, as in motorsports applications.
Accordingly, there is a need for a noise-cancelling microphone that is able to cope with sounds directed toward the cancelling side, but not the capture side. In addition, there is a need for a microphone that is able to overcome the effects of heavy wind and still produce a quality signal of the sound intended to be captured.
The foregoing objects and advantages of the invention are illustrative of those that can be achieved by the various exemplary embodiments and are not intended to be exhaustive or limiting of the possible advantages which can be realized. Thus, these and other objects and advantages of the various exemplary embodiments will be apparent from the description herein or can be learned from practicing the various exemplary embodiments, both as embodied herein or as modified in view of any variation that may be apparent to those skilled in the art. Accordingly, the present invention resides in the novel methods, arrangements, combinations, and improvements herein shown and described in various exemplary embodiments.